/*
 * This file is part of Adblock Plus <https://adblockplus.org/>,
 * Copyright (C) 2006-2015 Eyeo GmbH
 *
 * Adblock Plus is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 3 as
 * published by the Free Software Foundation.
 *
 * Adblock Plus is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.pl.adblocker.core;

import java.lang.ref.ReferenceQueue;
import java.lang.ref.WeakReference;
import java.util.HashSet;

public final class Disposer extends WeakReference<Disposable> {
	static final ReferenceQueue<Disposable> referenceQueue = new ReferenceQueue<Disposable>();
	private static final HashSet<Disposer> disposerSet = new HashSet<Disposer>();
	private final Disposable disposable;
	private volatile boolean disposed = false;

	static {
		final Thread thread = new Thread(new Cleaner());
		thread.setName(Cleaner.class.getCanonicalName());
		thread.setDaemon(true);
		thread.start();
	}

	public Disposer(final Disposable referent, final Disposable disposable) {
		super(referent, referenceQueue);
		this.disposable = disposable;

		synchronized (disposerSet) {
			disposerSet.add(this);
		}
	}

	public synchronized void dispose() {
		if (!this.disposed) {
			try {
				this.disposable.dispose();
			} catch (final Throwable t) {
				// catch to set state to 'disposed' on all circumstances
			}

			this.disposed = true;
			synchronized (disposerSet) {
				disposerSet.remove(this);
			}
		}
	}

	private static final class Cleaner implements Runnable {
		public Cleaner() {
			//
		}

		@Override
		public void run() {
			for (;;) {
				try {
					((Disposer) Disposer.referenceQueue.remove()).dispose();
				} catch (final Throwable t) {
					// ignored
				}
			}
		}
	}
}
